hie 
348 W. S&S. Sullivant on Nobert’s Test-plate. 
to resolve lines eloser together than about the ;;/,;; of an inch, 
ch. 
On the other hand, the late Professor J. W. Bailey claimed 
to have seen lines the ;,,';5; of an inch apart; and Messm 
Harrison and Sollitt claim to have measured. strie on the dia- 
tom Amphipleura pellucida having an interval of the rassv 
i and gave it as their opimon 
lines as close as the ;~;';;5 of an inch could, with prope 
means, be resolved. The above is learned from Mr, Stodders 
paper. 
accordance, obtained by the observers first mentioned, but 
reference to the claims made by Prof. Bailey and Messrs. : 
rison and Sollitt, it may be remarked that Prof, Bailey, though 
some of his micrometrical measurements ;* and with re 
to 
a 
ference that 
; 2 > Tr er ‘ yf 
anterior to the experiments reported in the pape than about 
; thet 
@ z5,455 of an inch, either on Nobert’s test-plate oF 2 by 
previous observers, the skill in manipulation and ” w, 60 dis 
agement of the illumination, &c., that brings to vie inch that 
tinctly and palpably, lines ruled to the ;yz!s07 f a found t0 
they have actually been counted and measured a? Fs 
1 
* Ho assigned to Pleurosigma Spencerii a striation of ever 1 2770 Jun, 
inch, the real striation being ay oes nia of an inch. (This a? 
1850). The striae of Grammatophora subtilissima are given had (this Jou 
ae = e inch apart instead of about +5}, the true distance, a 
n., ; : ve Amy 
+ Mr. Sobb, (Carpenter on the Microscope, 34 ed., p. 198) claims pee aaidinons 
pleura pellucida, Prof. H. L. Smith, of Gambier, Ohio, whose to this di 
: : ‘ tion : 
to microscopical apparatus are well known, has given much atten A 
tom; he recently witnessed Mr. Sobb’s alleged resolution of i as is the on | 
siders the lines exhibited as spectral or spurious, and 8U 
ion of Mr. Wenham. 
